The present invention relates to an apparatus for starting an internal combustion engine and, more particularly, to an improvement in a rope starting apparatus for starting a small-sized internal combustion engine.
Generally, small-sized internal combustion engines are provided with manually operable starting apparatus such as recoil starter using a rope. This rope starting device has a reel around which is wound a rope. As the rope is pulled, the reel is rotated to impact a starting inertia to the engine crank shaft through a clutch, thereby to start the engine. In this starting operation by pulling the rope with hand for rotating the crank shaft, a large load is imposed during the compression stroke of the engine to hinder the rotation of the engine crank shaft.
In order to facilitate the rotation of the crank shaft during the starting, the exhaust valve of the engine is temporarily kept opened to keep the engine in the state of decompression and, when a sufficient inertia is obtained, the exhaust valve is released to take operative position to dismiss the state of decompression thereby to start the engine. This device for temporarily keeping the exhaust valve in the opened position is usually referred to as "decompression device".
In starting an engine provided with both of rope starting device and decompression device, it is necessary to manipulate both devices simultaneously. This inevitably requires two operators for the starting operation.
Another problem concerning the rope starting device is that a strong impact is imparted to the arm of the operator pulling the rope when the crank shaft of the engine rotates beyond the top dead center in the compression stroke. An extremely large impact is given to the operator's arm dangerously particularly when the engine has a large compression ratio.